This disclosure relates to a hearing assistance system.
Some binaural hearing assistance systems have two earbuds (or other types of earpieces that deliver sound to an ear), one for each ear. Each earpiece has one or more microphones. The microphones on both ears can be used together to increase the performance of the system, for example by binaural beamforming. Some users, however, prefer a single-ear device due to reduced stigma, ease of conveying social availability, having only a unilateral hearing loss, or other motivation. Users who prefer to use only one earpiece in a system where two earpieces are in some manner connected, be that physically with a wire or through wireless communication, may leave the other earpiece to rest against the neck or shoulder, or hidden under a shirt, or placed in a pocket, or placed in a storage case, or “parked” to neckware that is part of the system via a magnet, mechanical connection, or other means. Doing so, however, creates problems for binaural beamforming and other processing which utilize microphones on both sides of the head to create the output signal for each ear. Namely, the “dropped” earpiece and its microphones are no longer pointing in the “look” direction of the array, and they are no longer in the same plane or position relative to the other-side microphones. These two issues negatively impact performance of the array for the ear audio signal into the assisted ear. Additionally, microphones of the “dropped” earpiece may be in close contact to surrounding objects (e.g., shirt, necklace), and interference with those objects could cause significant and objectionable noise to be generated in the assisted ear. Further, when an earbud is removed from the ear there is increased acoustic coupling between the driver output and external microphone input, which can cause objectionable audible oscillation due to acoustic feedback. Other algorithms, such as binaural steady-state noise suppressors, may also perform in a sub-optimal manner.